The present invention generally relates to a recording method for an optical disk and a recording and reproducing apparatus, and more particularly, to a recording method and a recording and reproducing apparatus, which are capable of a rewriting operation, applying upon an optical disk laser beams of approximately 1 micron in diameter, recording and reproducing signals of high density, and erasing once recorded signals by laser application, so that signals can be recorded and reproduced many times.
FIG. 9 (a) shows a block diagram of a recording system of the conventional optical disk recording and reproducing apparatus. A modulating circuit 101 is adapted to modulate an input data 108 in accordance with a modulation rule so as to output modulation data 109 in accordance with a request from a selector 104.
A fixed pattern producing circuit 102 produces a fixed pattern FM 110 in accordance with a request from the selector 104.
A synchronous signal producing circuit 103 produces a synchronous signal VFO 111 in accordance with a, request from the selector 104.
The selector 104 combines the modulation data 109, the fixed pattern FM 110, and the synchronous signal VFO 111 so as to output recording data 112.
A laser driving circuit 105 drives the semiconductor laser 106 in accordance with the recording data 112 to apply the recording data 112 upon the optical disk 107, so that, for example, the reflection ratio variation and so on are produced so as to effect the recording operation.
FIG. 9(b) shows a block diagram of a reproduction system of the conventional optical disk recording and reproducing apparatus.
A weak laser power is applied to the optical disk 107 so as to obtain a reproduction signal RF 118 through detecting the reflection light by an optical detector 113.
A binary coded circuit 114 codes the reproducing signal RF 118 into a binary coded signal DSG 119.
A PLL circuit 115 generates a reproduction reference clock CLK 120 from the binary coded signal DSG 119.
A fixed pattern detecting circuit 116 detects a fixed pattern FM 110 from the binary coded signal DSG 119 and the reproduction reference clock CLK 120 so as to produce the detection signal FMD 121.
A demodulating circuit 117 demodulates the binary coded signal DSG 119 from the reproduction reference clock CLK 120 and the detection signal FMD 121 so as to output the demodulation data.
FIG. 10(a) shows a data format recorded on the optical disk by the conventional optical disk recording and reproducing apparatus. The recording operation is effected in the order of a synchronous signal portion 44, a fixed pattern portion 45, a data 1 46a, a fixed pattern portion 45, a data 2 46b, . . . , a fixed pattern portion 45, and a data 46c, in succession subsequent to address portion 43 preformatted previously on the optical disk.
The synchronous signal VFO (FIG. 9, 111) is recorded on the synchronous signal portion 44 for use in the locking of the PLL circuit (FIG. 9, 115).
The fixed pattern FM (FIG. 9, 110) is normally recorded on the fixed pattern portion 45 so as to indicate the head of the data signal, and at the same time is used to synchronize the data signal.
FIG. 10(b) shows a concrete pattern 2-7-2-2 for the conventional fixed pattern FM (FIG. 9, 110) on the expression of (2-7) run-length-limited code as shown with D15 (Draft International Standard) 10089. The conventional fixed pattern is constructed in the fixed pattern of 2-7-2-2 in terms of the run length of zeros where the minimum run length of zeros 2 and the maximum run length of zeros 7 are adjacent to each other (i.e. having a 1 located therebetween), and the minimum run length of zeros 2 is adjacent to the other minimum run length of zeros 2.
FIG. 10(c) shows, for example, the modulation wave form of the laser when the conventional fixed pattern portion FM is actually recorded on a phase variation rewriting type optical disk. At the location of the data 0, the erasing power (comparatively low power) is applied to erase the previous data. At the location of the data 1, the recording power (comparatively high power) is applied so as to produce the recording pits. The state of the recording pits is shown in FIG. 10(d).